package day1108_4;

public class W3 {
    public static void main(String[] args) {
        double n=1;//代表1到20之间的每个数字(n不断增加n++)
        double result=0;//代表累加和
        while(n<=20){
            result=result+ (  1.0/(n* (n+1))   );
            n++;
        }
        System.out.println(result);
    }
}
//169.254.138.247        192.168.68.1